1. Field of the Invention
The present invention relates to a motorcycle clutch with linked foot and hand clutch actuators that enables foot or hand activation of a motorcycle clutch for installation on motorcycles that may use or have been retrofitted from a configuration of a hand activated clutch and foot activated gear selection lever, to a configuration of a foot activated clutch and hand activated gear selection lever. It employs coupled foot and hand mechanical linkages that eliminate impediments to precise and predictable clutch operation and imparts a high degree of safety in the operation of a motorcycle by allowing the clutch to be held in the disengaged position with either the left foot or left hand with the motorcycle running while in gear.
2. Description of the Prior Art
Contemporary motorcycles are generally equipped with mechanical clutches as part of the drive train, which provide the interface between the motor output shaft and the transmission. These clutches are activated by pulling a hand lever on the left handlebar, which in turn drives a cable that is attached to the clutch. Later motorcycles may also be equipped with a hydraulic link between the hand lever and the clutch. Gear selection on contemporary motorcycles is accomplished by the up and down movement of a foot pedal on the left side of the motorcycle. However, as late as the mid-1950s, vintage motorcycles were equipped with foot operated clutches and gear selection levers that were operated by hand. Such motorcycles include early Harley-Davidson™, Moto Guzzi™, Excelsior-Henderson™, BMW™ and Indian™ ™ motorcycles, in addition to many others.
Today the motorcycle world is trending to an appreciation of the form and function of vintage motorcycles. Motorcycle enthusiasts are increasingly attracted to “cruiser” class motorcycles that emulate the look of older motorcycles. To more closely mimic the vintage look, contemporary motorcyclists find themselves retrofitting their motorcycles with “aftermarket” foot clutches as well as gear selection levers that are actuated by hand.
Current aftermarket foot clutch actuators, for retrofitting of contemporary motorcycles, provide a link from a foot clutch pedal, generally on the left side of the motorcycle, via a cable within a flexible cable housing that is sharply arced to the side of the motorcycle where the cable connects with the clutch mechanism. The location to which the cable connects with the original equipment manufacturer clutch mechanism is generally behind the motor, on the right side of the motorcycle. When the foot pedal is activated, the cable transmits the force to the original equipment manufacturer motorcycle clutch, thereby allowing the motorcycle operator to change gears with the hand operated gear change lever.
However this configuration causes imprecise and rough clutch engagement because of flawed geometric relationships between the foot pedal and the insufficient arc of travel of the foot clutch pedal over the small displacement imparted to the clutch cable. This results in frequent stalls and erratic starts which may pose a safety issue.
In addition, since the position of the motorcycle clutch mechanism and transmission is behind the motor, this places the foot actuated clutch lever in front of and far removed from the clutch mechanism. Current aftermarket foot clutch actuators produce tremendous friction between the cable and cable housing over a sharp bend of up to 180 degrees. This results sluggish clutch engagement and lack of engagement feedback, further exacerbating accurate clutch actuation which results in frequent stalls and erratic starts.
Current aftermarket foot clutch actuators do not provide a means of holding the clutch in a disengaged position to allow both of the operator's feet on the ground to balance the motorcycle when stopped with the motor idling while still in gear.
Current aftermarket foot clutch actuators also do not provide a coupled hand clutch option for re-engaging the clutch from a stationary position.
Current aftermarket foot clutch actuators also do not provide a coupled hand clutch option for modulating the clutch during precision slow speed operations when both feet must be available for balancing the motorcycle.
Current aftermarket foot clutch actuators also do not provide a coupled hand clutch option for accomplishing an emergency stop, with motor running and the transmission in gear, thus allowing both feet to be free for balancing the motorcycle.
Current aftermarket foot clutch actuators do not provide a means of eliminating friction between a contorted control cable and cable housing, resulting in erratic clutch operation and vague clutch engagement feedback, which induce frequent stalls and erratic starts.
Current aftermarket foot clutch actuators do not provide the means of augmenting the original equipment manufacturer clutch spring(s) within the motorcycle clutch assembly, to return the foot clutch pedal to the engaged position.
Current aftermarket foot clutch actuators do not provide a means, such as a cam, to progressively reduce the rate of displacement of the control linkage while the clutch is being engaged, to enable more precise operation of the clutch.
Current aftermarket foot clutch actuators do not provide the means of transferring the force originating from the foot clutch pedal or the hand clutch lever from one elevation to another for the purpose of routing cables in the control linkage by straightest route to the original equipment manufacturer clutch assembly, thereby eliminating detrimental friction from contorted control cable housings which results in frequent stalls and erratic starts.
During an emergency scenario in which the motorcycle operator must abruptly stop and balance the motorcycle with both feet on the ground, he or she will not have time to find the neutral position on the transmission and will need to hold the clutch in the disengaged position while bringing the motorcycle to a complete stop. This action allows the engine to idle while still in gear. Conventional motorcycles with the modern foot gear shift, hand clutch configurations allow for emergency stops while the motorcycle is in gear and both feet are required on the ground after stopping, by the operator applying simultaneous positive pressure on the left hand clutch lever, right hand front brake lever and right foot rear brake lever. Before the motorcycle comes to a complete stop the motorcycle operator will have free use of both feet to balance the motorcycle while the clutch is held in the in the disengaged position with the left hand and the motorcycle is maintained motionless by means of the front hand brake while the motorcycle is idling and in gear.
During a routine planned stop, the motorcycle operator riding a modern motorcycle retrofitted with an aftermarket foot clutch actuator may have the presence of mind to find the neutral position on the transmission before stopping, allowing him or her to release the foot clutch and place both feet on the ground to balance the stopped motorcycle and maintain it in the motionless state by means of the front hand brake.
However in an emergency situation involving a modern motorcycle retrofitted with an existing aftermarket foot clutch actuator, wherein the operator must accomplish an abrupt stop with the motorcycle in gear, the operator would not be able to hold the clutch in the disengaged position with the left foot when both feet must be available for balancing the motorcycle. This scenario can result in either a total inability of the rider to stop the motorcycle altogether, or a much longer stopping distance since the motorcycle brakes would be working against the still engaged motor, or a stalled motorcycle. Either result endangers the motorcycle operator and rider as well as pedestrians and the motoring public.
U.S. Pat. No. 5,662,195 A (Shifter assembly conversion kit) describes a gear shift conversion kit and method for converting a foot-operated shift mechanism and a hand-operated clutch mechanism on a motorcycle to a hand-operated shift mechanism and a foot-operated clutch mechanism. The clutch actuation mechanism described in U.S. Pat. No. 5,662,195 A is limited to clutch actuation via foot control only and does not provide for dual clutch actuation capability via foot pedal and hand lever. Generally, this type of aftermarket clutch actuator imparts tremendous friction between the cable and cable housing resulting in lack of engagement feedback, further exacerbating inaccurate clutch actuation resulting in frequent stalls and erratic starts. In addition, this type of foot clutch configuration is limited by the small displacement of the arc of travel of the foot clutch pedal, preventing precise and smooth clutch re-engagement. This results in frequent stalls and erratic starts.
U.S. Pat. No. 4,316,531 A (Clutch lockout latch) is a manually operated latch mounted on the handlebar of a motorcycle to engage the hand clutch control lever for holding the clutch in a locked-out position or in a partially disengaged position. This invention allows for the motorcycle operator to put the hand operated clutch in the disengaged position without having to maintain positive pressure on hand clutch lever. The invention described in U.S. Pat. No. 4,316,531 is limited to clutch actuation via hand control only and does not provide for dual clutch actuation capability via foot pedal and hand lever. In addition this invention would not allow the rider to use a hand operated gear selection lever.
U.S. Pat. No. 2,540,926 A (Conversion unit for motorcycles) relates to an attachment for vintage (1940s & earlier) motorcycles to convert them from the foot clutch, hand gear shift configuration to hand clutch, foot gear shift configuration. This invention is the direct antithesis of what the present patent means to accomplish. In addition the invention described in U.S. Pat. No. 2,540,926 A is limited to clutch actuation via hand control only and does not provide for dual clutch actuation capability via foot pedal and hand lever. Furthermore, this invention eliminates the use of a hand operated gear selection lever.
U.S. Pat. No. 2,094,163 A (Gear controlling means for motorcycles) provides for coupled hand and foot controls for the gear selection on a motorcycle. Clutch actuation is accomplished with a hand lever on the handlebar. The invention described in U.S. Pat. No. 2,094,163 A is limited to clutch actuation via hand control only and does not provide for dual clutch actuation capability via foot pedal and hand lever.
U.S. Pat. No. 5,299,652 A (Motorcycle controls for physically challenged rider) relates to a handlebar control system for a motorcycle which enables complete control of the motorcycle without moving the hands from the handlebars. The invention described in U.S. Pat. No. 5,299,652 A does not provide for a foot operated clutch.
Patent number WO 2005100143 A1 (Motorcycle gear shift control) provides for a foot operated gear-shift assembly, gear shift conversion kit, and method for changing gear shifting actions of a conventional motorcycle wherein the heel and toe shift elements of the conventional rocker-arm gear shift assembly are separated and rotate about separate pivot axes. The invention described in patent number WO 2005100143 A1 simply alters the foot shift mechanism, and gear selection is still accomplished via foot control. This precludes the use of a foot operated clutch. In addition this invention does not provide for a hand operated gear selection lever.
U.S. Pat. No. 6,945,376 B1 (Foot Operated Motorcycle Clutch) is a foot-operated clutch mechanism to be installed on modern motorcycles to convert them from hand operated clutch to foot operated clutch. This mechanism is limited to clutch actuation via a foot pedal only and does not provide for dual clutch actuation capability via foot pedal and hand lever.
The custom motorcycle aftermarket also includes a hand operated gear selector lever with the hand operated clutch lever mounted to the gear selection lever. This configuration of hand clutch mounted on hand gear selection lever can be seen advertised in magazines, which cater to the custom motorcycle builder, such as “American Iron” and “Chopper”. This configuration requires the rider to initiate forward motion of a stationary motorcycle by engaging the clutch with the left hand away from the handlebar and only the right hand controlling the direction of the motorcycle. This embodiment makes it impossible to safely maneuver the motorcycle in very slow speed situations that require both feet on the ground and both hands on the handlebars while modulating the clutch. In addition this embodiment is limited to clutch actuation via hand control only and does not provide for dual clutch actuation capability via foot pedal and hand lever.